Hosts still unbeaten but weakness exposed
Although they were just 10 minutes from a potential win, a pensive start, porous midfield and defensive frailties ultimately cost the host nation a famous victory in front of almost 85,000 spectators at a noisy Soccer City stadium.
Siphiwe Tshabalala's goal in the 55th minute did provide a glimpse of the potential of a team who looked comfortable on the ball once they had found a rhythm with their short passing game in the second half.
But there was far too much desperate defending and ball chasing from the lowly-ranked Bafana Bafana to suggest they could prove a surprise package at their own World Cup, even if they have not lost since last October.
South Africa were also fortunate that Mexico's much vaunted strike force failed to deliver, leaving defender Rafael Marquez to grab a deserved share of the spoils.
The 79th minute equaliser put the lid on a potential explosion of joy from the home nation but ensured a fair result in an opening match that set a dramatic standard for the remainder of the month-long tournament.
Marquez scored from close range as the South African defence were caught totally out of position, achieving where his younger attacking colleagues had failed despite overwhelming possession.
The strike force of Carlos Vela and Guillermo Franco were largely overshadowed by the quick-paced enterprise of Giovani dos Santos, who proved fleet-footed and dangerous.
He might have scored as early as the second minute, denied only by a desperate challenge from South African captain Aaron Mokoena.
Mokoena, in his 102nd appearance, spent much of the cold winter afternoon making desperate tackles to stymie the Mexicans but was at fault for the goal when he completely missed an attempted headed clearance and Marquez stole in behind him to score.
Mexico's quick interchanging of positions persistently flummoxed the South African defence while a timid approach from the hosts at times saw them repeatedly overrun in midfield.
"They are the most daring team in this World Cup," South Africa's coach Carlos Alberto Parreira said of the opponents.
At left back, Parreira's gamble with Lucas Thwala threatened to undo months of intense work in the build-up to the tournament, including injecting a new-found of self belief in the South Africans.
But after substituting Thwala with Tsepo Masilela at half-time, the hosts announced their potential with some quick passing of their own.
Their goal came on the counter attack, though, with Tshabalala speeding away before cracking home an angled effort from the left.
The tempo of the game was kept high right to the end, despite the energy-sapping altitude and there might have been a dramatic late winner for Katlego Mphela, whose effort hit the upright in the final minute.
South Africa next play Uruguay in Pretoria on Wednesday while Mexico will meet France in Polokwane on Thursday.
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